Novel molybdenum–cerium based heterogeneous catalysts for efficient oxidative coupling of benzylamines under eco-friendly conditions

This work demonstrates that MoOx/CeO2ZrO2 solid acid acts as a promising catalyst in the solvent-free oxidative-coupling of benzylamine into diben-zylimine with O-2 as the oxidant. The benzylamine conversions were found to be 27, 51, 74, and 99 % for CeO2, CeO2-ZrO2, MoOx/CeO2, and MoOx/CeO2-ZrO2 catalysts, respectively. The MoOx/CeO2-ZrO2 catalyst also efficiently converts various substituted- and secondary-benzylamines under solvent-free conditions with 02 resulting in moderate to excellent yields. Remarkably, a high selectivity of similar to 99.6-99.9 % towards the dibenzylimine product was found for all reaction conditions. The outstanding performance of MoOx/CeO2-ZrO2 catalyst was attributed to high specific surface area, improved structural defects, and superior acid properties.